ABSTRACT
Increased calorie utilization generally leads to increased appetite and food intake. However, the Gl hypermotility brought about by high titers of thyroid hormones frequently leads to vomiting and diarrhea. The glomerular filtration rate is reportedly increased in many hyperthyroid animals, and high titers of thyroid hormones may decrease the concentrating ability of the nephron. Therefore, medullary washout can occur, leading to polyuria and secondary polydipsia (PU/PD). Vomiting and diarrhea also cause dehydration, which again increases thirst. The cause of azotemia (increased BUN and serum creatinine) in animals with thyrotoxicosis is not as well understood. It has been postulated that increased protein catabolism may contribute. Azotemia is more likely to occur following treatment for the hyperthyroid state, and therefore renal function should be carefully assessed before, during, and following therapy.
